The present invention relates generally to reducing pressure valves or to an automatic regulating valve which reduces pressure on a primary side to a predetermined pressure on a secondary side by changing the opening of a valve through the energy of the fluid itself which passes therethrough.
Reducing valves generally include two types. One is a direct-acting type wherein a secondary pressure detecting section itself becomes an operating section which directly actuates a valve member. The second is a pilot-operated type wherein, using a direct-acting reducing valve as a pilot section, the main valve member is operated by regiulating the pressure in a main valve operating section. The present invention involves the construction of a connecting section between a valve member and the operating section of such valves and is applicable to both direct-acting reducing valves and pilot-operated reducing valves.
The invention relates generally to improvements in the offset characteristics and rated flow characteristics of the reducing valve.
In the art to which the present invention relates, the following terms shall have the following meanings (source: Heating, Air-Conditioning and Sanitary Standard HASS 106-1978):
Minimum regulatable flow rate: PA1 Set Pressure: PA1 Offset: PA1 Rated flow rate:
Minimum flow rate of the reducing valve at which a steady state of flow can be maintained. PA2 A pressure on the secondary side at the minimum regulatable flow rate. PA2 The difference between the set presure and the pressure on the secondary side which varies as the flow rate is gradually increased from the minimum regulatable flow rate to the rated flow rate of the reducing valve with the pressure on the primary side held constant. PA2 Maximum flow rate that can be assured within a specific offset when the pressure on the primary side is held fixed.
In the context discussed above, a good reducing valve is one which has low offset and a high rated flow rate.
It has been found that in valves in accordance with the prior art, the flow rate characteristics show a relatively large offset and a relatively small rated flow rate. Limitations on the flow rate characteristics are presumed to arise due to certain structural characteristics of prior art valves, and, accordingly, the present invention is directed toward improving the flow rate characteristics of prior art reducing valves by providing an improved structural configuration for the related parts thereof.
U.S. Pat. No. 3,262,464 to Frantz shows a drain valve having a movable valve member which has small and large diameter guidance portions that slide in respective cylinders to firmly support the valve member against jamming. A curved annular surface is provided on the valve member in Frantz for engaging a valve seat. No particular dimensional relationship is provided between the curved portion and the guiding portions of the valve member in Frantz and no indication is given that the curved surface would aid in avoiding jamming or rattling when the valve is closing.
U.S. Pat. No. 3,291,153 to Chabrier et al. shows the use of spherical valve members in a fluid actuated oscillator.